1 files changed, 69 insertions, 0 deletions
diff --git a/src/math/mp_numth.cpp b/src/math/mp_numth.cpp
new file mode 100644
index 000000000..b024d2e2d
--- /dev/null
+++ b/src/math/mp_numth.cpp
@@ -0,0 +1,69 @@
+/*************************************************
+* Fused and Important MP Algorithms Source File  *
+* (C) 1999-2007 Jack Lloyd                       *
+*************************************************/
+
+#include <botan/numthry.h>
+#include <botan/mp_core.h>
+#include <botan/util.h>
+#include <algorithm>
+
+namespace Botan {
+
+/*************************************************
+* Square a BigInt                                *
+*************************************************/
+BigInt square(const BigInt& x)
+   {
+   const u32bit x_sw = x.sig_words();
+
+   BigInt z(BigInt::Positive, round_up(2*x_sw, 16));
+   SecureVector<word> workspace(z.size());
+
+   bigint_sqr(z.get_reg(), z.size(), workspace,
+              x.data(), x.size(), x_sw);
+   return z;
+   }
+
+/*************************************************
+* Multiply-Add Operation                         *
+*************************************************/
+BigInt mul_add(const BigInt& a, const BigInt& b, const BigInt& c)
+   {
+   if(c.is_negative() || c.is_zero())
+      throw Invalid_Argument("mul_add: Third argument must be > 0");
+
+   BigInt::Sign sign = BigInt::Positive;
+   if(a.sign() != b.sign())
+      sign = BigInt::Negative;
+
+   const u32bit a_sw = a.sig_words();
+   const u32bit b_sw = b.sig_words();
+   const u32bit c_sw = c.sig_words();
+
+   BigInt r(sign, std::max(a.size() + b.size(), c_sw) + 1);
+   SecureVector<word> workspace(r.size());
+
+   bigint_mul(r.get_reg(), r.size(), workspace,
+              a.data(), a.size(), a_sw,
+              b.data(), b.size(), b_sw);
+   const u32bit r_size = std::max(r.sig_words(), c_sw);
+   bigint_add2(r.get_reg(), r_size, c.data(), c_sw);
+   return r;
+   }
+
+/*************************************************
+* Subtract-Multiply Operation                    *
+*************************************************/
+BigInt sub_mul(const BigInt& a, const BigInt& b, const BigInt& c)
+   {
+   if(a.is_negative() || b.is_negative())
+      throw Invalid_Argument("sub_mul: First two arguments must be >= 0");
+
+   BigInt r = a;
+   r -= b;
+   r *= c;
+   return r;
+   }
+
+}